The invention relates to paving vehicles, and more particularly to mobile conveyor systems used with road paving vehicles.
Paving vehicles or xe2x80x9cpaversxe2x80x9d are well known and basically function to deposit, level and compact paving material, typically asphalt or concrete, onto a base surface (e.g., a road bed) so as to form a mat of paving material. Paving vehicles generally include a front-mounted hopper inside which a quantity of paving material is temporarily held. During a paving operation, the paving material is conveyed from the hopper to the rear of the vehicle and is deposited onto a base surface for leveling by a screed towed from the paver. As such, the quantity of material in the hopper is continuously consumed during the paving operation so that the hopper must be re-supplied with paving material. To keep the paver hopper supplied with paving material, one of the following methods is generally used.
First, a dump truck may be backed up to the front of the paver, allowing material to be directly dumped or deposited into the hopper from the bed or bin of the truck. Using a dump truck to periodically refill the paver hopper requires that the truck driver carefully backs up to the paver and adjusts the truck speed to match the paver travel speed in order to avoid colliding with the paver, such collisions generally causing ripples to form in the material mat. The second common approach is to use a second vehicle, commonly referred to as a xe2x80x9cmaterial transferxe2x80x9d vehicle, which travels forwardly of the paver during the entire paver operation and continuously conveys material from an on-board hopper to the paver hopper. The transfer vehicle hopper is then intermittently re-supplied with material by a dump truck, and any collisions between the transfer vehicle and the dump truck will generally not effect the quality of the pavement formed by the paver as the transfer vehicle and paver are not connected.
In general, such transfer vehicles include a chassis, a hopper mounted to the front of the chassis and a conveyor extending longitudinally from the hopper to the rear of the chassis. The conveyor has a inlet end disposed in the hopper and a discharge end extending over the rear of the chassis, the conveyor being inclined such that the discharge end is spaced higher than the inlet end. As such, when the material transfer vehicle is located forwardly of the paver, the discharge end of the transfer vehicle conveyor is located above the paver hopper, allowing paving material to be conveyed from the transfer vehicle hopper to fall-off the discharge end and into the paver hopper.
In certain applications, it is necessary to convey material from a transfer vehicle to a paver travelling parallel to the transfer vehicle, i.e., to a paver arranged offset to one side of the transfer vehicle rather than generally behind the vehicle. Examples of such situations are when the roadbed being paved is too soft for a dump truck to travel upon or when paving over a barrier, where a truck is too large to reach. To accomplish this, the transfer vehicle is either provided with a second, rotatable conveyor mounted on the vehicle chassis to the rear of the first or primary conveyor, or a separate conveyor assembly is towed from the rear of the transfer vehicle. In either case, the second conveyor, referred to as a xe2x80x9cswingxe2x80x9d conveyor, is able to rotate or swing to either side of the transfer vehicle to enable material to be transported to the offset paver. Although both of these methods of transferring paving material to an offset paver have been useful, each approach has certain limitations or drawbacks, as follows.
With a transfer vehicle having a second conveyor mounted directly on the chassis of the transfer vehicle, the transfer vehicle is more complex and generally requires the second conveyor to be used at all times, even when the paver is following directly behind the transfer vehicle in a standard paving operation. As such, the second, unnecessary conveying operation on the transfer vehicle results in wasted power consumption and excessive wear on the second conveyor. A separately towed conveyor has the advantage of being removable so that only the primary conveyor is used for a standard paving operation, but also has certain drawbacks. One limitation is that known towed conveyors generally either have only a limited range of rotation, such that the swing conveyor cannot reach a full 90xc2x0 to either side, or a full rotation requires certain adjustment of mechanisms for rotating the conveyor, thereby requiring set-up time to adjust the swing conveyor as desired. Another drawback with towed conveyors is that the conveyor generally rolls upon two fixed or non-steerable wheels, such that the towed conveyor is unable to be follow the transfer vehicle when the vehicle is travelling a curved path, causing the swing conveyor to drift to one side of the vehicle and potentially moving the conveyor inlet end from beneath the primary conveyor discharge end as required.
Therefore, it would be desirable to provide a towed or xe2x80x9cmobilexe2x80x9d conveyor that overcomes the limitations of previously known towed conveyors.
In a first aspect, the present invention is a mobile conveyor assembly for use with a construction vehicle. The vehicle has a wheel pivotable about a pivot axis and a steering actuator configured to pivot the wheel about the axis. The conveyor assembly comprises a carriage removably connectable with the vehicle and having a wheel pivotable about a pivot axis. A conveyor is mounted to the carriage. Further, a steering actuator is connected with the carriage wheel and is operably connectable with the vehicle actuator. The carriage actuator is configured to pivot the carriage wheel about the carriage wheel pivot axis in a first angular direction when the vehicle actuator pivots the vehicle wheel about the vehicle wheel pivot axis in a second, opposing angular direction.
In another aspect, the present invention is a construction vehicle assembly comprising a first frame having at least one wheel pivotable about a first pivot axis. A first steering actuator is configured to pivot the wheel about the axis. A second frame is removably connectable with the first frame and has at least one wheel pivotable about a second pivot axis. Further, a second steering actuator is operatively connected with the second frame wheel and operably connectable with the first steering actuator. The second steering actuator is configured to pivot the second frame wheel about the second pivot axis in a first angular direction when the first steering actuator pivots the first frame wheel about the first wheel pivot axis in a second, opposing angular direction.
In yet another aspect, the present invention is a conveyor assembly comprising a base having a pivot axis and a first circumferential bearing surface extending at least partially about the axis. A conveyor is rotatably connected with the base and has a second circumferential bearing surface slidably disposed against the first bearing surface. The second bearing surface is displaceable with respect to the first bearing surface along a first arcuate path having a first radius about the pivot axis. An actuator has an end connected with the base and is configured to rotate the conveyor about the axis such that the second bearing surface displaces along the first arcuate path as the actuator end displaces along a second arcuate path having a second radius about the axis. The first path radius is substantially greater than the second path radius such that a magnitude of the second bearing surface displacement is substantially greater than a magnitude of the actuator end displacement.
In an even further aspect, the present invention is a also conveyor assembly comprising a base having a pivot axis and a first, generally annular bearing body connected with the base and substantially centered about the axis. A conveyor has a second generally annular bearing body slidably engaged with the first bearing body to rotatably connect the conveyor to the base. Further, an actuator has a first end connected with the base and a second end connected with the conveyor, the second end being disposed generally between the second bearing body and the axis. The actuator is configured to displace the second end with respect to the first end so as to rotatably displace the conveyor about the axis as the second bearing body slidably displaces with respect to the first bearing body.
In yet an even further aspect, the present invention is also a conveyor assembly comprising a conveyor base having a conveyor swing axis and a first circumferential bearing surface extending at least partially about the axis. A conveyor body is rotatably connected with the base and has a second circumferential bearing surface, the second bearing surface being slidably disposed against the first bearing surface and generally centered about the swing axis by a first radial distance. Further, a hydraulic cylinder has a cylinder body connected with the base and a rod displaceable with respect to the rod, the rod being connected with the conveyor at a position spaced from the swing axis by a second radial distance. The first radial distance is substantially greater than the second radial distance such that displacement of the rod angularly displaces the conveyor about the swing axis as the second circumferential surface linearly displaces with respect to the first circumferential surface. As such, a magnitude of displacement of the second circumferential surface is substantially greater than a magnitude of displacement of the rod.
In a yet another further aspect, the present invention is again a mobile conveyor assembly for use with the construction vehicle. The conveyor assembly comprises a carriage removably connectable with the vehicle and having a wheel pivotable about a pivot axis, a swing axis and a first circumferential bearing surface extending at least partially about the swing axis. A steering actuator is connected with the carriage wheel and operably connectable with the vehicle actuator, the carriage actuator being configured to pivot the carriage wheel about the carriage wheel pivot axis in a first angular direction when the vehicle actuator pivots the vehicle wheel about the vehicle wheel pivot axis in a second, opposing angular direction. Further, a conveyor is rotatably connected with the base and having a second circumferential bearing surface slidably disposed against the first bearing surface, the second bearing surface being linearly displaceable with respect to the first bearing surface along a first arcuate path having a first radius about the pivot axis. Furthermore, a swing actuator has an end connected with the conveyor, the actuator being configured to angularly displace the conveyor about the swing axis such that the second bearing surface linearly displaces along the first arcuate path as the actuator end linearly displaces along a second arcuate path having a second radius about the axis. The first path radius is substantially greater than the second path radius such that a magnitude of the second bearing surface linear displacement is substantially greater than a magnitude of the actuator end linear displacement.